The invention relates to a method of, and apparatus for, moistening loose material; and in particular to a method of, and apparatus for, applying glue to loose fibrous material.
It is know to coat loose material, such as fibrous material, with glue by rotary spraying of the glue. For example, glue applying apparatus is known in which glue is flung out and broken into droplets by means of tools secured to a rotating shaft, the tools having longitudinal bores. The shaft is rotatably mounted in a container through which the loose material passes. The individual droplets of glue leave the tools one after the other, and at roughly equal distances apart along a specific path. The path of travel of each of the fluid droplets is determined by the speed of revolution of the shaft, and by its mass.
Since the individual droplets are flung away from the tools at very short distances apart, they almost form a jet which is sprayed substantially radially in a single plane. Unfortunately, it is highly probable that parts of the loose material that is to be treated are moistened by several very fine droplets before these parts have moved forward through the container. In the glue-coating of fibrous material, in which the glue is not distributed by a wiping effect between the individual small pieces of fibre, this phenomenon lead to overconcentration of glue at individual points, and therefore to a defective (speckled) surface of the boards formed from the fibrous material.
An object of the invention is to improve the moistening of loose material; and, in particular, the coating of fibrous material with glue so that a loose material, moistened more uniformly than has hitherto been possible, and in particular an extremely uniformly glue-coated fibrous material can be produced.